The invention relates to an arrangement for open-end rotor spinning having a spinning rotor, the open side of which is covered by a cover part that is provided with a projection projecting into the spinning rotor, which contains a fiber feeding duct and a yarn withdrawal duct.
A known rotor spinning arrangement is depicted in DE-OS No. 24 55 528 which represents the conventional method of construction of most of today's open-end rotor spinning arrangements. The withdrawal nozzle is made of a wear-resistant material, such as a ceramic material or the like, and is equipped with a thread lug by means of which it is threaded into the projection of the cover part. The fiber feeding duct extends laterally past the yarn withdrawal duct that centrically passes through the projection. In practice, today it is often preferable to use spinning rotors with an increasingly smaller diameter, i.e., rotors having a decreased inside diameter of the fiber collecting groove. Using small spinning rotors of this type that, if necessary, may have a diameter of less than 30 mm, the rotational rotor speed may be increased to more than 100,000 min.sup.-1. With the diminishing diameter of the spinning rotor, the projection of the cover part that projects into the spinning rotor must naturally also become smaller. Practical problems arise with respect to the housing of both the yarn withdrawal duct and the fiber feeding duct, in which case, particularly the latter cannot be reduced arbitrarily in comparison to the conventional size because the air proportions in the spinning arrangement would no longer be correct.
It is also known (DE-OS No. 27 45 195) to hold a withdrawal nozzle magnetically. In the case of one construction, the withdrawal nozzle is surrounded by an enclosure consisting of a ferromagnetic material and is held magnetically on the end of a hollow shaft that projects into the spinning rotor. The yarn withdrawal takes place through this hollow shaft. In the case of another construction, in which the yarn withdrawal takes place through a cover of the spinning rotor, the withdrawal nozzle is held in a bush consisting of a magnetic material that is inserted into the cover, the withdrawal nozzle being inserted into this bush. Both constructions require space that does not exist at a projection that is to protrude into a spinning rotor that has a very small diameter.
An object of the present invention is to provide a spinning apparatus such that the fiber feeding duct and the yarn withdrawal duct can both be housed in a projection that has a small diameter and a small axial length with respect to the spinning rotor axis.
This object is achieved by fastening a yarn withdrawal nozzle at a cover part by means of a holding element other than the yarn withdrawal nozzle.
Using the present invention, it becomes possible to reduce the space requirement for the withdrawal nozzle, particularly because the withdrawal nozzle no longer has to be screwed into the projection of the cover part by an external thread, i.e. no longer the withdrawal nozzle itself forms the holding element. The withdrawal nozzle may therefore be shorter and also mainly be smaller in its diameter following the inlet area, so that sufficient space exists in the projection in order to house a fiber feeding duct having a relatively large cross-section. The holding element can therefore be constructed and arranged such that it does not limit the existing space.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.